Shuji Nakamura: The Man Who Gave Us The Blue LED Despite All Odds

With the invention of the first LED featuring a red color, it seemed only a matter of time before LEDs would appear with other colors. Indeed, soon green and other colors joined the LED revolution, but not blue. Although some dim prototypes existed, none of them were practical enough to be considered for commercialization. The subject of a recent [Veritasium] video, the core of the problem was that finding a material with the right bandgap and other desirable properties remained elusive. It was in this situation that at the tail end of the 1980s a young engineer at Nichia in Japan found himself pursuing a solution to this conundrum.

Although Nichia was struggling at the time due to the competition in the semiconductor market, its president was not afraid to take a gamble on a promise, which is why this young engineer – [Shuji Nakamura] – got permission to try his wits at the problem. This included a year long study trip to Florida to learn the ins and outs of a new technology called metalorganic chemical vapor deposition (MOCVD, also metalorganic vapor-phase epitaxy). Once back in Japan, he got access to a new MOCVD machine at Nichia, which he quickly got around to heavily modifying into the now well-known two-flow reactor version which improves the yield.

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Pimp My Pot Redux, Now Cheaper And Even Better

If there’s one thing we like around here more than seeing an improved version of a project we’ve already covered, it’s when the improvements make the original project cheaper. In the case of this LED ring light for pots and encoders, not only is it cheaper than its predecessors, it’s better looking and easier to integrate into your projects.

Right from its start, [upir]’s “Pimp My Pot” project has been all about bringing some zazzle to rotary controls. Knobs with a pointer and a scale on the panel are okay — especially when they go to eleven — but more lights mean more fun. The fun comes at a price, though; the previous version of “PMP” used an off-the-shelf LED ring light with a unit cost of about $10. Not the end of the world, perhaps, but prohibitive, and besides, where’s the fun in just buying a component specifically made for rotary control indication?

The new version shown in the video below is pin-compatible with the driver board [upir] used for the previous version, which is based on the MAX7219 display driver. Modifying the previous board to accommodate 32 white 0402 LEDs over a 270° arc was no mean feat. [upir] covers both creating the schematic and the PCB layout in some detail, providing his usual trove of tool-chain tips for minimizing the amount of manual work needed.

Wisely, [upir] chose to get his boards assembled by the vendor; getting all those LEDs to line up perfectly is a job best left to the robots. While the board is designed for use with pots that mount on either side, we much prefer mounting the pot’s shaft through the board, as it keeps the LEDs closer to the knob. The final price per board works out to about $6.30 in quantities of ten and falls to a trivial $1.70 each for lots of 1,000. Pretty sweet savings on a pretty sweet-looking build.

This is a cool use of a ring of LEDs, but if you prefer the finger kind, you can make that, too. You can do it the easy way or the hard way.

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Wooden Desk Lamp Uses Unusual Dimmer

One of the problems with laser cutting projects is that while they look good, they often look like they were laser cut. [Timber Rough] has a wooden desk lamp that not only looks good but has one of the most unusual dimming features we’ve seen.

One thing that stands out is the lamp is made of different kinds of wood, and that helps. But the dimmer is a magnet and Hall effect sensor that levitates. It is hard to explain, but a quick look at the video below will clarify it.

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Building Nanoleaf-Inspired Wall Panels That Look Great

Nanoleaf is well-known as being that company that makes those lovely glowing tiles that you can hang on your wall. The only thing is, they’re not cheap. So if you want a really cool layout, you have to spend a great amount of money. [Projects with Red] was inspired by the basic concept, though, and whipped up their own gem-shaped wall tiles along similar lines.

The devices can work as a big clock if you so desire.

The irregular hexagon shape of each gem has ten connection points to attach the segments together. Physical connections are made using the 3D printed housings of each segment, while connections are simply made with wires and connectors hanging out the back for flexibility.

Each segment features a black printed housing with a solid lid and a translucent acrylic sheet to act as a diffuser. An addressable LED strip is mounted to the lid for illumination, with Dupont connectors for hooking them up to power and data. An ESP32 is used to drive the addressable LED chain, running the WLED.me software for easy control of the lights and animations. The video below also explains how to configure the segments into a giant colorful 7-segment display.

It’s a neat way to build some LED wall art, with plenty of scope to reconfigure it to suit your own needs. We’ve seen some other fun LED tile projects before, too.
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A Look At 3D Printed Professional LED Signage

Customer perception is everything when you’re running a business, particularly in retail. High-quality signage can go a long way into creating a good impression in this respect. [king process] decided to show us how professional-grade LED signage is made in a Korean shop that specializes in the work.

The signs we’re shown are custom builds that are matched to the shape of a company’s logo. No rectangular printed lightboxes here, this is fully custom stuff. To that end, a 3D printer is the perfect tool for the job, as it lets the shop produce signs in any shape desired with no need for custom tooling.

The 3D printers that build up the signs have seriously large build volumes, though more so in the X and Y dimensions rather than the Z. We see a whole fleet of printers working away to allow multiple signs to be produced quickly. The first step is to produce the outline of a sign, which serves as a base for the build. Cavities in the sign are then filled with a translucent silicone solution to act as diffuser material. Once cured, these various sections are colored by hand as required. LED strips are then installed on a backing plate to illuminate the sections of the sign.

The final result is a sign with clean, bright glowing lines. It’s vaguely reminiscent of a neon sign, but without any of the limitations of the glass tubes influencing how it looks. It’s also neat to see the techniques a professional shop uses to make things right the first time, without dinging or marring any of the parts along the way.

Indeed, it seems the classical neon sign is, these days, bested by a variety of alternative technologies.

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The Simple Tech Behind Hidden Camera Detectors

If you’ve ever been concerned about privacy in a rental space or hotel room, you might have considered trying one of the many “spy camera detectors” sold online. In the video after break [Big Clive], tears one down and gives us  an in-depth look at how these gadgets actually work, and their limitations.

Most detector follow the same basic design: a ring of LEDs through which the user inspects a room, looking for reflections indicating a potential hidden camera. Although this device can help spot a camera, it’s not entirely foolproof. The work best when you’re close to the center of a camera’s field of view, and some other objects, like large LEDs can produce similar reflections

The model examined in this video takes things one step further by adding a disc of dichroic glass. Coated with a metallization layer close to the wavelength of the LEDs, it effectively acts a bandpass filter, reducing reflections from other light sources. [Big Clive] also does his customary reverse-engineering of the circuit, which is just a simple flasher powered by USB-C.

[Big Clive]’s teardowns are always an educational experience, like we’ve seen in his videos on LED bulb circuits and a fake CO2 sensor.

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1D Fireworks Are Nice And Quiet

Maybe you do it out of respect for the dogs and parents of young children in the neighborhood. Or maybe you do it because they’re harmful to the environment, or just because it’s too darn cold outside. Whatever your reasoning for not setting off fireworks, don’t fret — you can probably put together your own silent one-dimensional “fireworks” display from what you’ve got in the parts bin.

[Daniel Westhof]’s design is simple, requiring little more than a Wemos D1 Mini and a strip of WS2812 LEDs. Once activated, a red rocket shoots up from the ground and detonates, sending lights in both directions on the strip to imitate the bombs bursting in air. It’s controlled with a small push button switch, and there’s a deliciously large red LED indicator that shows the thing is ready for detonation.

You might be surprised to find that there’s a wide array of 1D gaming and animation projects out there, many of which made possible by the ubiquitous addressable RGB LED strip. We’ve seen a dungeon crawler, at least two different versions of the classic PONG, and even the makings of a simplified Wolfenstein.